Animal and plant natural raw materials for food contain many useful hydrophobic edible materials. Usually, these hydrophobic edible materials are separated from raw materials by, for example, extraction and, optionally, concentrated and then consumed as food or their additives. However, due to hydrophobic nature, most of them have no or little water solubility and dispersibility, which results in low absorption into the body.
Further, there are many hydrophobic edible materials which are valuable not only from the nutritional viewpoint but also from medical and health viewpoints. However, many of them have inferior taste and palatability and are not suitable for food or their additives.
The present inventors have endeavored to improve water solubility and dispersibility of these hydrophobic edible materials and thereby to improve absorption thereof in the body as well as to improve their taste and palatability. As result, it has been found that, when a water soluble ingredient selected from the group consisting of water soluble low molecular weight peptides, water soluble concentrated extracts and mixtures thereof are admixed with hydrophobic edible materials, particularly, those obtained by extraction with a fluid at subcritical or supercritical conditions, water solubility and dispersibility of the hydrophobic edible materials and absorption thereof into the body as well as taste and palatability are remarkably improved.
Extraction of hydrophobic edible materials by using subcritical or supercritical conditions is known. For example, Japanese Patent Kokoku No. 51-33185 discloses extraction of coffee oil from roasted coffee beans. Japanese Patent Kokoku No. 54-10539 discloses a fundamental technique of extraction of using a fluid at subcritical or supercritical conditions. Further, Japanese Patent Kokoku No. 55-16200 discloses extraction of fats and oils from animal or plant raw materials by using a fluid at subcritical or supercritical conditions. Angew. Chem. Int. Ed. Engl. 17, 716-727 (1978) discloses a review of extraction with a fluid at subcritical and supercritical conditions. U.S. Pat. No. 4,714,791 of the present applicant (the assignee of the present application) also discloses the production of aliphatic higher alcohols by using a fluid at subcritical and supercritical conditions. U.S. patent application Ser. No. 078,189 of the present applicant discloses a method for treating glycosides with a fluid at subcritical and supercritical conditions. However, the prior art does not teach improvement of water solubility and dispersibility or improvement of taste and palatability of hydrophobic edible materials by addition of the above water soluble ingredient.